A number of industry drivers including increased deployment of renewable energy generation, costs for managing grid peak demands, capital investments in grid infrastructure for reliability and smart grid initiatives are creating renewed interest in electric energy storage systems. There is no energy storage technology today that can provide all of the requirements for high-amperage, large scale energy storage systems for wide-spread non-geography specific use.
While many technologies are in the research phase, the only conventional energy storage technology expected to be commercially viable today is hydro storage, especially via dam up-rating, and underground pumping. However, very high initial costs and poor scalability makes pumped hydro suitable only at some specific locations.